1. Field of the Disclosure
The present invention relates to a touch panel, more particularly, to a touch panel having improved sensitivity embodied by applying divisional driving to a large-sized touch panel and changing a structure of a divided border area between divided areas while the divisional driving is implemented, and a liquid crystal display device including the touch panel.
2. Discussion of the Related Art
As the information age has started in earnest, a display field used to express an electrical information signal visually has been developed drastically. Together with that, a variety of flat display devices having excellent functions of slimming, reduced weights and low electricity consumption has been developed and they replace conventional cathode ray tube (CRT) devices rapidly.
Such a flat display device includes a liquid crystal display device (LCD), a plasma display panel device (PDP), a field emission display device (FED), an electro luminescence display device (ELD) and the like. They are commonly configured of a flay display panel to present images and this flat display panel has a couple of transparent insulating substrates boned with each other with a luminescent or polarizing material layer formed there between.
The liquid crystal display device (LCD) displays images by controlling light transmisivity of liquid crystal by way of an electric field. For that, the liquid crystal display device includes a liquid display panel having liquid crystal cells, a back light unit configured to emit lights to the display panel and a driving circuit configured to the liquid crystal cells.
A plurality unit pixel regions are defined and formed in the liquid crystal display panel by gate lines and data lines alternatively aligned to each other. At this time, each pixel region includes a thin film transistor array substrate, a color filter array substrate, a spacer located between the two substrates to maintain a cell gap and liquid crystal filled in the cell gap.
The thin film array substrate is configured of gate lines and data lines, a thin film transistor formed in each cross point of the gate and data lines as switch device, a pixel electrode connected with the thin film transistor with being formed in liquid crystal cell units, and an alignment layer coated thereon. The gate and data lines receive a signal from driving circuits via pad parts, respectively.
The thin transistor transmits a pixel voltage signal supplied to the data lines to the pixel electrode in response to a scan signal supplied to the gate lines.
The color filter substrate is configured of color filters formed in the liquid crystal cell units, a black matrix configured to distinguish color filters from each other and to reflect external lights, common electrodes configured to supply a reference voltage to each of the liquid crystal cells commonly and an alignment layer coated thereon.
After the thin film transistor substrate and the color filter array substrate fabricated independently as mentioned above are alignedly bonded to each other in opposite, the liquid crystal is injected and sealed.
Recently, such the liquid display device has been required to have a touch panel capable of recognizing a touch point inputted by a finger or auxiliary inputting means and of transmitting information corresponding to the touch. This touch panel is configured to be attached to an outer surface of the liquid crystal display device.
The touch panel may be categorized based on a touch sensing type into a resistance type, a capacitive type and an infrared sensor type. Recently, the capacitive type has been receiving attention to be applied to a compact sized model, in consideration of manufacturing convenience and sensitivity.
As follows, the capacitive type touch panel of related art will be described in reference to the accompanying drawing.
FIG. 1 is a plan view schematically illustrating the capacitive type touch panel of related art.
As shown in FIG. 1, the capacitive type touch panel of related art includes first electrodes 11 and second electrodes 12 aligned to each other on a substrate 10, a pad electrode 40 provided in a predetermined area of the substrate 10 to be connected with a flexible printed circuit (FPC) 50 including a touch controller 51. The first and second electrodes 11 and 12 are connected with the pad electrode 40 via a routing wire 25.
The first and second electrodes 11 and 12 may be aligned to each other in a bar shape, or they may be aligned in a rhombus pattern corresponding to sensing regions, respectively, as shown in FIG. 1, such that one electrode is formed to have a thin connection pattern integrally formed with a neighboring rhombus pattern and the other electrode is formed to electrically connect the neighboring rhombus pattern adjacent to the connection pattern with a connection metal pattern 21 of the other metal.
Here, the touch controller 51 may be a kind of an integrated circuit (IC) including input pins (not shown) as connecting parts of a driving part provided in the display device and output pins (not shown, which are in contact with the pad electrode) configured to apply signals to the first and second electrodes 11 and 12.
However, the touch controller 51 typically used at moment supports the number of pins (channels) proper to a compact-sized model. Especially, as demands of touch solution development with respect to a compact-sized model such as a mobile phone have been stronger in recent, most touch controller developers have developed the touch controller 51 proper to the compact models.
In the current market, demands of touch panel technology have been increasing more and more in industries of net books, NBPC (notebook PC) models and monitors. In contrast, development of touch controller IC proper even to a middle and large sized model has not accomplished yet. Because of that, considering touch resolution and photolysis, application of medium-and-large-sized models is impossible in the current IC development level.
FIG. 2 is a diagram illustrating comparison between an area of a predetermined sensing region and a contact area of an actual finger, when the capacitive type touch panel of related art is applied to a more-than-medium sized model.
For example, according to FIG. 2, the first and second electrodes are formed in the rhombus pattern, corresponding to the sensing regions, respectively. An electrode is formed to have the thin connection pattern integrally formed with a neighboring rhombus pattern and the other electrode is formed by electrically connecting the neighboring pattern with a connection metal pattern of another metal with respect to an intersection of the connection pattern.
In this case, currently commercialized IC of the touch controller has the fixed number of channels (pins). Because of that, as the size of the model is larger, the sizes of the first and second electrodes have to be larger for the sensing, corresponding to such the number of the channels.
According to FIG. 2, each diagonal line of the first and second electrodes provided for this sensing is approximately 1.5 cm in a single sensing region 31 of the touch panel presented to be proper to the number of the pins of the touch controller.
However, a critical dimension of a finger in a single touch area is approximately 1 cm. As this is applied to the structure shown in FIG. 2, the area of the sensing region is formed larger than the single touch area of the finger. If a minute region moves because of the finger touching, it is impossible to detect the minute moving and it is expected for touch sensitivity to be deteriorated.
Furthermore, the capacitive type touch panel of related art has a problem of impossible multi-touch.
FIGS. 3A and 3B are diagrams illustrating touching in a self capacitive type and detecting areas thereof.
As shown in FIG. 3A, for example, A(5a) and B(5b) points of a finger touches different areas simultaneously and then the self capacitive type applies a signal and detects the signal for all lines of the first electrodes (X electrodes) and second electrodes (Y electrodes). At this time, signal application and detection is implemented in the first electrodes and after that, signal application and detection is implemented in the second electrodes.
If the touch of the finger A(5a) and B(5b) implemented simultaneously, each of the first and second electrodes reads a changing value from lines where the finger A and B (5a and 5b) are located. As shown in FIG. 3B, crossing areas (G) of the lines where the finger A and B are located are recognized as touch, together with the actual touch Area®.
That is, the crossing rear (G) of the lines having the finger located therein is a ghost point, not the actual touch point, and this ghost phenomenon is getting severer as the number of the multi-touches is getting larger.